How to connect fax machine WITHOUT a regular phone line

I have an HP 6210 MFC (fax machine). I don’t have a regular phone line anymore. I do have Comcast cable with a Linksys wireless router connected to it. I have a PC with a fax/modem inside, but of course no RJ-11 wire connected to it. I have 2 PCs. One XP connected via wire to router. One Vista connected via 802.11n to router. The MFC is connected to the XP machine via USB and serves as a printer. I’d like to use the MFC to send & RECIEVE faxes. I’ve heard of a possible solution called MajicJack (www.majicjack.com) but not sure if it will work. Will this, or something else, enable me to have a phone # that I can use to send/receive faxes w/ my MFC?